Many types of input devices are presently available for performing operations in a computing system, such as buttons or keys, mice, trackballs, joysticks, touch sensor panels, touch screens and the like. Touch panels, in particular, are becoming increasingly popular because of their ease and versatility of operation as well as their declining price. Touch screens can include a clear panel with a touch-sensitive surface. A computer or another type of electronic device can process signals generated by the touch panel to determine how and where a user is touching the touch panel.
A multi-touch panel is an advanced type of touch panel that allows multiple touch events to be sensed at the touch panel at the same time. A multi-touch panel allows for more complex user interaction, as it allows an electronic device to detect all areas of a panel that are being touched at any given time. Thus, an electronic device can obtain an “image” indicating the positions and shapes of all touches taking place on a panel at any given time. Furthermore, a multi-touch panel or a device connected thereto can track the movement of one or more touch events over time (e.g., one or more fingers being moved along the surface of the panel). This may allow the tracking of more complex “touch gestures.”
Various types of multi-touch panels can be designed. One type provides for sensing touch events based on sensing changes of capacitance caused by a finger or another object touching the panel. An exemplary multi-touch panel of this type is discussed in U.S. application Ser. No. 11/649,998, Pub. No. 20080158172 filed Jan. 3, 2007, the contents of which are incorporated by reference herein in their entirety for all purposes.
While touch sensing (whether single or multi-touch) is undoubtedly beneficial; in certain situations touch sensing may gather too much information. For example, the user may touch the panel or move his/her fingers along the panel unintentionally or at least without intending to convey this action to the computer or device. If the device responds to unintentional actions by the user it may confuse the user or misinterpret commands or other communications received from the user.